We evaluated 41 patients with history of another known malignancy (gastrointestinal, 23; breast, 11; other, 7) referred with an incidental thyroid nodule. Patients underwent office-based US and biopsy of nodules ≥1 cm. Surgical intervention was based on biopsy results. We compared nodule size at pathology with size seen on CT or US.
Thirty-five patients met criteria for biopsy. Of the 35, 20 (57 % ) had atypical biopsy results warranting resection. Sixteen of those 20 underwent surgery. Pathology yielded 4 papillary thyroid cancers (PTC), 4 microPTC, 2 metastatic cancers, and 7 benign lesions. Ultrasound measurement of nodules compared to size measured at pathology had an r2 correlation value of 0.90 with P value <.0001. CT scan had an r2 value of 0.83 and P value of .005.
Incidental thyroid nodules in patients with another primary malignancy warranted resection in 57 % . The rate of malignancy in incidental thyroid nodules was 24 % , which is above the expected rate of 5 % seen in traditionally discovered nodules. US correlation with nodule size at pathology was excellent and superior to CT scan. Incidentally discovered thyroid nodules ≥1 cm, seen in patients with another malignancy, warrant further evaluation.